<?php

class Entity_Base {
  
  /**
   * this function check if a field is in the data sent in the constructor
   * you can specify an array, and this function will use like alias
   */
  protected function validateField($field, $default = false) {
    $fieldIsEmpty = true;
    
    // this is a trick, if $fields is a string, $fields will be an array with
    // one element
    if (is_array ( $field )) {
      $fields = $field;
    }
    else {
      $fields = array ();
      $fields [] = $field;
    }
    
    // if there are aliases for this field, evaluate all aliases and take the
    // first occurence
    foreach ( $fields as $k => $f ) {
      if (isset ( $this->temp [$f] )) {
        $fieldIsEmpty = false;
        return $this->temp [$f];
      }
    }
    
    // field empty means the user has not sent a value for this Field, so we are
    // using the default value
    if ($fieldIsEmpty) {
      if ($default !== false) {
        return $default;
      }
    }
  }
  
  protected function validateRequiredFields($requiredFields = array()) {
    foreach ( $requiredFields as $k => $field ) {
      if ($this->{$field} === NULL) {
        throw (new Exception ( "Field $field is required in " . get_class ( $this ) ));
        die ();
      }
    }
  }
  
  /**
   *
   *
   * Copy the values of the Entity to the array of aliases
   * The array of aliases must be defined.
   *
   * @return Array of alias with the Entity values
   */
  public function getAliasDataArray() {
    $aAlias = array ();
    // get aliases from class
    $className = get_class ( $this );
    if (method_exists ( $className, 'GetAliases' )) {
      $aliases = call_user_func(array($className, 'GetAliases'));
      //$aliases = $className::GetAliases ();
      foreach ( $this as $field => $value )
        if (isset ( $aliases [$field] )) {
          // echo "Field exists in Aliases: " . $field . "\n";
          // echo "Alias Name:" . $aliases[$field] . "\n";
          // echo "Alias value:" . $value . "\n";
          $aAlias [$aliases [$field]] = $value;
        }
    }
    
    return $aAlias;
  }
  
  /**
   *
   *
   * Set the data from array of alias to Entity
   *
   * @param $aAliasData array
   *          of data of aliases
   */
  public function setAliasDataArray($aAliasData) {
    // get aliases from class
    $className = get_class ( $this );
    if (method_exists ( $className, 'GetAliases' )) {
      $aliases = call_user_func(array($className, 'GetAliases'));
      //$aliases = $className::GetAliases ();
      foreach ( $this as $field => $value )
        if (isset ( $aliases [$field] ))
          $this->{$field} = $aAliasData [$aliases [$field]];
    }
  }
  
  /**
   *
   *
   * Initialize object with values from $data.
   * The values from data use properties or alias array.
   * 
   * @param
   *          $data
   */
  protected function initializeObject($data) {
    // get aliases from class
    $className = get_class ( $this );
    $aliases = array ();
    $swAliases = false;
    if (method_exists ( $className, 'GetAliases' )) {
      $aliases = call_user_func(array($className, 'GetAliases'));
      //$aliases = $className::GetAliases ();
      $swAliases = true;
    }
    // use object properties or aliases to initialize
    foreach ( $this as $field => $value )
      if (isset ( $data [$field] )) {
        $this->$field = $data [$field];
      }
      elseif ($swAliases && isset ( $aliases [$field] ) && isset ( $data [$aliases [$field]] )) {
        $this->$field = $data [$aliases [$field]];
      }
  }
  
  public function serialize() {
    if (isset ( $this->temp ))
      unset ( $this->temp );
    return serialize ( $this );
  }
  
  public function unserialize($str) {
    $className = get_class ( $this );
    $data = unserialize ( $str );
    return new $className ( $data );
  }

}